To meet the demand for natural resources, companies often invest significant amounts of time and money in searching for and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired resource is discovered below the surface of the earth, drilling and production systems are often employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource. Further, such systems generally include a completion system that includes wellhead assembly through which the resource is extracted. These completion systems may include a wide variety of components, such as various casings, hangers, valves, fluid conduits, and the like, that control drilling and/or extraction operations.
One type of completion assembly includes a wellhead with one or more strings of casing supported by casing hangers in the wellhead. Attached to the wellhead is a tubing spool and a tubing hanger secured to a string of tubing lands in the tubing spool above the wellhead. The tubing hanger has a plurality of vertical passages that surround a vertical bore. The vertical fluid passages provide access through the tubing hanger for hydraulic fluid or electrical lines to operate and control equipment located downhole such a safety valves or chemical injection units. Electrical and/or hydraulic control lines extend below the tubing hanger alongside the outside of the tubing to control downhole valves, temperature sensors, and the like.
A production tree is installed on top of the tubing spool. The production tree has a vertical bore that receives upward flow of fluid from the tubing string and tubing hanger. The tree has valves for controlling flow from the well. The vertical passages in the tubing hanger connect with vertical connectors protruding downward from the tree. The passages in the tree are in communication with a control unit in the tree.